1. Field of the Invention
The present invention relates to a driver safety apparatus for a vehicle, and, more particularly, to a safety belt apparatus for a vehicle provided with an air bag system for protecting the driver of the vehicle against injury in case of collision.
2. Description of Related Art
In recent years, a driver safety apparatus, including a safety air bag device, in addition to a safety belt device, has been installed in a vehicle to protect the driver of the vehicle against injury during a collision. An air bag of the air bag safety device is housed, when empty, in a container provided in, for instance, the steering wheel or the instrument panel of the vehicle. The air bag is quickly inflated by compressed gas on the occurrence of a collision. The safety air bag and safety belt can serve in combination to prevent the driver from being thrown out of the driver's seat during a straight-on, front end collision. Such a safety apparatus is known from Japanese Unexamined Patent Publication No. 62(1987)-139740.
During the use of the combination of safety belt device and safety air bag device, the driver is likely to be subjected to an abrupt, high pressure impact on his or her breast during a collision. This is because upon the occurrence of a collision, the air bag needs time before it is completely inflated and acts on the driver's breast as the driver plunges out of the seat toward the steering wheel. The time required for the air bag to inflate is slightly longer than the time in which the safety belt device acts quickly on the driver's breast. This results in doubled, abrupt applications of impact forces against the driver's breast. From the viewpoint of restraining or holding down the driver in the driver's seat, it is desirable that the safety device should not exert any abrupt, considerably high pressure impact on the driver.